1345961 – xfsprogs: mkfs option changes

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Bug 1345961 - xfsprogs: mkfs option changes

Summary: xfsprogs: mkfs option changes

Keywords:
Status:	CLOSED ERRATA
Alias:	None
Product:	Red Hat Enterprise Linux 7
Classification:	Red Hat
Component:	xfsprogs
Sub Component:
Version:	7.3
Hardware:	Unspecified
OS:	Unspecified
Priority:	unspecified
Severity:	unspecified
Target Milestone:	rc
Target Release:	---
Assignee:	Eric Sandeen
QA Contact:	Zorro Lang
Docs Contact:	Milan Navratil
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+	depends on / blocked

Reported:	2016-06-13 13:57 UTC by Eric Sandeen
Modified:	2016-11-04 06:24 UTC (History)
CC List:	5 users (show)
Fixed In Version:
Doc Type:	Release Note
Doc Text:	The sparse inode feature as well as the "finobt" feature are now disabled by default in mkfs.xfs With this update, the sparse inode feature is disabled, and the "finobt" feature is turned off by default in the mkfs.xfs utility. The "finobt" option enables the use of a separate free inode btree index in each allocation group, which allows for a higher and more consistent inode allocation performance as file systems age because used nodes are not indexed. By default, mkfs.xfs does note create free inode btrees for file systems to ensure compatibility with earlier Red Hat Enterprise Linux 7 kernel versions, which cannot mount such file systems.
Clone Of:
Environment:
Last Closed:	2016-11-04 06:24:22 UTC
Target Upstream Version:
Embargoed:

Attachments	(Terms of Use)

Links
System	ID	Private	Priority	Status	Summary	Last Updated
Red Hat Product Errata	RHBA-2016:2431	0	normal	SHIPPED_LIVE	xfsprogs bug fix and enhancement update	2016-11-03 14:00:51 UTC

Description Eric Sandeen 2016-06-13 13:57:20 UTC

We do not yet wish to support the experimental sparse inode feature in mkfs.xfs from xfsprogs 4.5.0, and we probably want to disable the finobt feature by default, because using that option results in filesystems which cannot be mounted by older RHEL7 kernels.

This needs a little more discussion within the filesystem team, but this is the likely outcome:

1) disable the sparse inode feature in mkfs.xfs
2) make the finobt feature in mkfs.xfs non-default

Comment 3 Eric Sandeen 2016-08-08 14:32:02 UTC

From the mkfs.xfs(8) manpage in the package:

                   finobt=value
                          This option enables the use of a separate free inode
                          btree index in each allocation group. The  value  is
                          either  0  to  disable the feature, or 1 to create a
                          free inode btree in each allocation group.

                          The free inode btree mirrors the existing  allocated
                          inode  btree  index which indexes both used and free
                          inodes. The free inode btree  does  not  index  used
                          inodes, allowing faster, more consistent inode allo-
                          cation performance as filesystems age.

                          By default, mkfs.xfs  will  not  create  free  inode
                          btrees  for filesystems.  This is for backwards com-
                          patibility with older RHEL7 kernels.   If  the  free
                          inode btree is enabled, older RHEL7 kernels will not
                          be able to mount the created filesystem.   When  the
                          option  -m  crc=0 is used, the free inode btree fea-
                          ture is not supported and is disabled.

Does that suffice for your purposes?

Comment 4 Eric Sandeen 2016-08-08 15:04:24 UTC

I'm not quite sure what the request is here: Document the feature, or document the defaults deviation from upstream, or both?

The above documents the feature sufficiently, I think, and notes that it is off by default in RHEL7.

Comment 6 Eric Sandeen 2016-08-11 17:33:59 UTC

thanks for the first pass at the doc text.

thinking about this some more, I think the goal here is to clarify what users are getting, and any differences that exist vs prior releases, and vs. the same version upstream.  So maybe something that adds information like:

---
In RHEL7.3, the xfsprogs package has been updated to version 4.5.0.  The following behavioral differences exist in the RHEL7.3 release as compared to upstream:

1) the experimental sparse inode feature is not available
2) the free inode btree (finobt) feature remains off by default in this release to ensure compatibility with older RHEL7 kernels.

<add finobt description here if you like>
---

(if "upstream" means anything to our customers?  not sure) :)

To clarify a bit more, finobt was available as a mkfs option in RHEL7.2.  Upstream it became default, but we left it optional in our release.  The "spinodes" option was not available before, and became available upstream, but we left it unavailable.  Those are the primary pieces of information here, I think.

Comment 8 Zorro Lang 2016-09-19 06:23:22 UTC

As this bug description said, this bug will do:
1) disable the sparse inode feature in mkfs.xfs
2) make the finobt feature in mkfs.xfs non-default

The test result on RHEL-7.3 snapshot4:
[root@ibm-p8-kvm-03-guest-08 ~]# mkfs.xfs -f /dev/vda5
meta-data=/dev/vda5              isize=512    agcount=4, agsize=983040 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0, sparse=0
data     =                       bsize=4096   blocks=3932160, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal log           bsize=4096   blocks=2560, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0

[root@ibm-p8-kvm-03-guest-08 ~]# man mkfs.xfs
  sparse[=value]
    Enable sparse inode chunk allocation. This experimental option is not available in RHEL7.

[root@ibm-p8-kvm-03-guest-08 ~]# mkfs.xfs -f -i sparse=1 /dev/vda5
unknown option -i sparse=1
...

All as expected, so verified this bug.

Comment 11 errata-xmlrpc 2016-11-04 06:24:22 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2016-2431.html

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